Transport of Dirac magnons driven by gauge fields

We present a unified quantum field theory for Dirac magnons coupled to emergent gauge fields. At zero temperature, any space- and time-dependent gauge perturbation drives magnons out of equilibrium, generating spin currents and magnon accumulation without conventional thermal or chemical potential gradients. For a honeycomb ferromagnet, we derive closed-form expressions for the induced density and current. In the DC limit, the transverse spin conductivity quantizes to $σ^{xy}=α^2\text{sgn}(m)\hbar/4π$, a magnonic analog of the quantum Hall effect, where $m$ is the topological magnon mass and $α$ a dimensionless coupling constant. In the AC regime, the conductivity exhibits a sharp resonance when the drive frequency matches the topological gap $Δ$, signaling interband transitions. Our work establishes gauge fields as a versatile tool for controlling magnon transport and reveals topologically protected quantized responses.

💡 Research Summary

The manuscript develops a unified quantum‑field‑theoretic framework for Dirac magnons interacting with generic emergent gauge fields. Starting from a minimal‑coupling Lagrangian (L=\bar\psi(i\hbar\tilde\gamma^\mu\partial_\mu-m)\psi-g\bar\psi\tilde\gamma^\mu\psi A_\mu), the authors integrate out the magnon fields and obtain a second‑order effective action (S_{\rm eff}^{(2)}